5 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Chariton | 1 | 4,340 | 4,189 | 0.7% | 1,152 | 3.77 | City |
| Russell | 2 | 475 | 472 | 0.21% | 463 | 1.02 | City |
| Lucas | 3 | 175 | 172 | 0.57% | 178 | 0.98 | City |
| Williamson | 4 | 129 | 118 | 1.57% | 339 | 0.38 | City |
| Derby | 5 | 89 | 88 | 0% | 349 | 0.26 | City |
Chariton is the largest city in Lucas County, with a population of 4,340.
Derby is the smallest city in Lucas County.
There are 5 cities in Lucas County, Iowa.